Male pattern baldness (MPB) affects 60-80% of the male caucasian population with advancing age. Anderson, R. D., Clin. Plast. Surg. 1987:14,(3):447. Various etiologies for MPB have been proposed which include age, genetics, androgens and scalp tension. In particular, in 1942 and 1951, it was reported that the etiology of MPB was related to an interdependent relationship of age, genetic predisposition and androgens. Hamilton, J. B., Am. J. Anat. 1942:71:451-480 and Hamilton, J. B. Ann NY Acad. Sci. 1951:53:708. It was found that MPB would not occur unless androgens were present and that androgens would not induce MPB without genetic predisposition. In 1959 it was postulated that MPB was linked to an androgen-sensitive, genetically pre-disposed senescence of hair follicles. These genetically predisposed hair follicles were located in the frontal and crown regions of the scalp. This theory (sometimes called "Donor Dominance") has prevailed for over thirty years.
Most treatment modalities currently employed (such as hair transplantation) have been performed based on this theory. However, transplantation methods are somewhat complex and no single treatment modality has proven completely or repeatably successful in inducing, maintaining and/or increasing hair growth.
More recently, in 1980, the reversal of MPB in a male patient receiving minoxidil for hypertension was revealed and minoxidil has since been used to promote hair growth, most commonly by topical application. Zapacosta, A. R., N. Eng. J. Med. 1980:303:1480-1481. Minoxidil's vasodilating effect on the scalp is one of the proposed mechanisms by which minoxidil promotes hair growth. However, despite its popularity, minoxidil has not performed in a completely satisfactory fashion in promoting hair growth in all target populations.
In summary, although various etiologies for baldness have been proposed and many treatments based on these etiologies attempted, the underlying pathophysiologies which cause baldness have not been elucidated. It is clear that without the identification of such pathophysiologies, no single treatment could be developed.
It would thus be desirable to develop a predictable method for treating baldness including male pattern baldness by promoting hair growth. It would also be desirable to develop a method for promoting hair growth based on the here-to-fore unrecognized pathophysiology which appears to cause baldness once identified.